Studies on poly(vinyl chloride)/fatty acid blends as shape-stabilized phase change material for latent heat thermal energy storage

The present study aims to prepare novel shape-stabilized phase change materials (PCMs) by using fatty acids [(lauric acid (LA), myristic acid (MA), palmitic acid (PA) and stearic acid (SA)] as PCM and poly(vinyl chloride) (PVC) as supporting material, and to determine their thermal properties such as melting temperature and the latent heat storage capacity. The maximum composition ratio of all fatty acids in the shape-stabilized PCMs has been found as 50 wt% in which no leakage of fatty acid is observed over their melting temperatures for several heating cycles. The miscibility of fatty acids with the PVC and the interaction between the blend components which is responsible for the miscibility has been proved by microscopic investigation and Infrared (IR) spectroscopy. The melting temperature and the latent heat of fusion of the shape-stabilized PCMs are measured by differential scanning calorimetry (DSC) analysis method. The melting temperatures and latent heats of the shape-stabilized PVC/LA, PVC/MA, PVC/PA and PVC/SA (50/50 wt%) PCMs are determined as 38.8, 49.2, 54.4 and 64.7°C and 97.8, 103.2, 120.3 and 129.3 J/g, respectively. The results indicate that the PVC/fatty acids blends as shape-stabilized PCMs have great potential for passive solar thermal energy applications in terms of their satisfactory thermal properties and advantages of easy preparation with desirable dimensions and direct utility in LHTES applications.